In a current cellular system, a base station includes a macro base station and a micro base station. Because distances from different mobile terminals to the base station are different, interference to different mobile terminals is different, which causes that channel quality of different mobile terminals is different. In addition, in some cases, some mobile terminals may not be covered by a base station, for example, a mobile terminal falls in a coverage hole area, or a base station is damaged for some special reasons, such as an earthquake. Such a mobile terminal that is not covered needs another mobile terminal to help access a network. A mobile terminal that is not covered or weakly covered is defined as an access mobile terminal, and a mobile terminal that can connect to a base station to access a network and can help the access mobile terminal access the network is defined as a base-station mobile terminal.
Because the access mobile terminal needs the base-station mobile terminal to help access a network, the access mobile terminal needs to discover the base-station mobile terminal and also needs to establish a connection to the base-station mobile terminal, and in this way, a final aim of accessing the network by the access mobile terminal can be implemented. Currently, an existing discovering manner for mobile terminals is mainly a manner in which mobile terminals autonomously discover each other. Each mobile terminal sends a beacon channel on a specific resource, so as to discover each other by checking beacon channels of each other.
Because a beacon channel resource is limited, it is necessary to check, before a mobile terminal sends a beacon channel, whether there is a beacon channel resource, and if there is a beacon channel resource, the mobile terminal sends the beacon channel. In this way, a disadvantage of a distributed manner for autonomously using a beacon channel by a mobile terminal is that a mobile terminal may use a beacon channel but does not establish a connection to another mobile terminal, thereby wasting the beacon channel.